This style is made by request. It is the ISO 960 numeric referencing style with square brackets.
Copy the style to your Word 2007 style directory, open Word 2007 and select 'ISO 690 - Numerical with Square Brackets' from the reference tab.
The latter can be useful if you plan on editing the numbers by hand afterwards.
The Word 2007 style directory is often located at 'C:\Program Files\Microsoft Office\Office12\Bibliography\Style'